Method of rolling shaped steel members having flanges

ABSTRACT

A method of rolling shaped steel members having flanges by a universal rolling mill, wherein the biting point of the web of the to-be-rolled material by horizontal rolls of said universal rolling mill precede that of the flange of the material by its vertical rolls, such precedence being adjusted by the ratio between the diameter of the vertical rolls and the horizontal rolls and/or the reduction schedule of each rolling pass.

United States Paten Kishikawa et a1.

[ 5 1 July 25, 1972 [54] METHOD OF ROLLING SHAPED STEEL MEMBERS HAVING FLANGES inventors: Kanichi Kishikawa; Takeo Kuwata; Kentaro Kinoshita, all of Kitakyushu City; Takao Tsuchiya; Yoshiro Kamogawn, both of Sakai City, all of Japan Assignee: Nippon Steel Corporation, Tokyo, Japan Filed: Dec. 2, 1969 App]. No.: 881,378

Foreign Application Priority Data Dec. 10, 1968 Japan ..43/90428 U.S. Cl ..72/225 Int. Cl ..B2lb 13/10 Field of Search ..72/225, 224, 234

References Cited UNITED STATES PATENTS 7/1912 Grey ..'...72/225 l/l889 Reese ..72/225 10/1915 Dunn ..72/225 12/1915 Cromwell ....72/225 1/1965 Kishikawa ..72/225 Primary Examiner-Milton S. Mehr Attorney-Wenderoth, Lind & Ponack ABSTRACT A method of rolling shaped steel members having flanges by a universal rolling mill, wherein the biting point of the web of the to-be-rolled material by horizontal rolls of said universal rolling mill precede that of the flange of the material by its vertical rolls, such precedence being adjusted by the ratio between the diameter of the vertical rolls and the horizontal rolls and/or the reduction schedule of each rolling pass.

1 Claim, 12 Drawing Figures Patented July 25, 1972 3,673,721

5 Sheets-Sheet 1 PRIOR ART 1 KANICHI kISi-llR-VA,

I l TAKEO KUWATA,

P KENTARO KINOSHITA, TAKAO TSUCHIYA and YOSHIRO KAMOGAWA,

INVENTOR s MM,ZlM

ATTORNEY S Patented July 25, 1972 FIG. 2A

5 Sheets-Sheet 2 7 'T; 'HI

. i PRIOR ART KANICHI KISHIKAWA- INVENTOR S TAKEO KUWATA, KENTARO KINOSHITA, TAKAO TSUCHIYA an d YOSHIRO KAMOGAWA,

"wmmw MM ATIURNIaY Patented July 25, 1972 3,678,721

5 Sheets-Sheet 5 .mllliihizz-f TF0 1 2 I FT Two KANICHI KISHIKAWA, 'IAKEO KUWATA, KENTARO KINOSHITA, TAKAO TSUCHIYA and YOSHIRO KAMOGAWA,

INVENTORS ATTORNEY S Patented July 25, 1972 5 Sheets-Sheet 4 a, a m @E i d i 1% M w ll h 8 on swsa 5;?

i .1 w @E E3 me KANICHI KISHIKAWA, INVENTORs TAKEO KUWATA, KENTARO KINOSHITA, TAKAO TSUCHIYA and YOSHIRO KAMOGAWA, filluhM MM ATTORNEY S Patented July 25, 1972 5 Sheets-Sheet 5 FIG. 7

PRIOR ART -SW(mm) KANICHI KISHIKAWA, TAKEO KUWATA, KENTARO KINOSHITA, TAKAO TSUCHIYA and YOSHIRO KAMOGAWA,

ZIJMMM UM ATTORNEYS INVENTOIE BACKGROUND OF THE INVENTION 1 Field of the Invention The present invention relates in general to a method of rolling shaped steel members having flanges, and more particularly to a method of rolling shaped steel members having flanges such as H-sectioned steel members and rails to be very accurately in size and shape by using the universal rolling mill.

2. Description of the Prior Art Publicly known is the method of rolling H-sectioned steel members and some kinds of rails having flanges by using the universal rolling mill having vertical rolls to roll the to-berolled material from both sides and horizontal rolls to roll the material from above and below.

The universal rolling mill of this kind is far advanced from that of the conventional rolling mill of the roll pass type in such respects as rolling technique, cost, and management or designing of the rolling passes. Particularly as shaped steel products are produced in larger sizes nowadays, the rolling method using the universal rolling mill is very important and indespensable in this field. However, this method has such shortcomings that the steel members produced thereby are generally not accurate in size and shape, and there frequently occur defects near the crossing area of the flange and web of such members.

SUMMARY OF THE INVENTION The object of the present invention is to provide a'method of rolling shaped steel members having flanges such'as H-sectioned steel members and rails by using the universal rolling mill, as an improvement of the conventional rolling method using the universal rolling mill, so that accuracy of the size and shape of the so rolled products can be raised, such improved method also being economical.

In order to attain this object, the method of the present invention is directed to the rolling of shaped steel members such as H-sectioned steel members and rails by a universal rolling mill having vertical rolls and horizontal rolls with their axes set on the same or nearly the same vertical section. The biting point of the web of the material by the horizontal rolls of the universal rolling mill is made precedent to that of the flange by the vertical rolls. This is accomplished by adjusting the ratio between the diameters of the vertical rolls and the horizontal roll and/or the reduction schedule of each rolling pass.

BRIEF DESCRIPTION OF THE DRAWING FIGS. IA and B show the rolling of a H-sectioned steel member by a universal rolling mill of conventional type FIG. IA shows the biting of the to-be-rolled material by the vertical rolls and FIG. 18 shows the biting of the to-be-rolled material by the horizontal rolls.

FIGS. 2A and B show the rolling operation by the conventional method FIG. 2A shows the vertical section of such operation and FIG. 2B shows its plane figure.

FIGS. 3A and B show the rolling of a H-sectioned steel member by the universal rolling mill according to the present invention FIG. 3A shows the biting of the to-be-rolled material by the vertical rolls and FIG. 3B shows the biting of the to-be-rolled material by the horizontal rolls.

FIG. 4 shows an explanatory diagram of the rolling operation of the horizontal rolls and the vertical rolls by the conventional method.

FIG. 5 shows an explanatory diagram of such operation according to the present invention.

FIG. 6 shows the friction power produced between each roll and the to-be-rolled material in operation.

FIG. 7 shows a histogram of the shifting of the web from the center in rolling a H-sectioned steel member by the universal rolling mill of conventional type.

FIG. 8 shows such histogram prepared on the same conditionsbut according to the present invention.

FIG. 9 shows the shifting of the web from the center in the direction of length of a H-sectioned steel member, in comparison between the case of rolling by the rolling mill of conventional type and the case of rolling by the rolling millof the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT As a result of studies on the causes of defective operation of the rolling method using the universal rolling mill of conventional type, it is found that such defective operation is caused generally by the ratio between the diameter of the vertical roll RV and the that of the horizontal roll RH being greater than 0.7 (RV/RH O.7), therefore, the contacting point of the flange with the vertical roll being greatly precedent to that of the web with the horizontal roll.

The above case of rolling a H-sectioned steel member is described more in detail, suing the drawings, as follows:

FIGS. IA and B show the relations between the tobe-rolled material and the vertical rolls of a universal rolling mill of conventional type and between the material and the horizontal rolls of the same rolling mill. In the rolling mill, all these rolls are arranged to be on the same vertical section, but, for convenience, the relation between the vertical rolls V and the tobe-rolled material and that between the horizontal rolls H and the material are separated, and shown respectively in FIG. IA andFIG. IB.

As seen in the drawings, the contacting points of the vertical rolls V with the flange of the to-be-rolled material are in- I dicated with Y,Y,- and the contacting points of the horizontal rolls with the material are indicated with Y -Y Thus, their projected contacting lengths are ldV and IdH. There are not given actual figures, but the general value of IdV/ldH is about 1.51. The flange contacts the vertical roll V in advance of the webs contact with the horizontal rolls by the distance converted from the above :ratio. However, such phenomenon brings about the following problems.

Firstly, as shown in FIGS. 2A and B, before the horizontal rolls H contact the web 2 of the to-be-rolled material, the metal of the flanges of the material is pushed by the vertical rolls V into the space] between the upper horizontal roll H and the lower horizontal roll H these horizontal rolls pressing said material to cause piling flaws.

Secondly, the inside 3 of the flange I of the to-be-rolled material and the side wall of the horizontal roll H contacting the inside 3 of said flange are pressed together from the outside of the flange by the vertical rolls V, the side wall of the horizontal rolls H making the inside 3 of said flange slide down in the direction of the web to cause scratches.

Thirdly, there is caused a lack of uniformity in the shape of the products. Such lack of uniformity is mostly due to the shifting of the web against the flange. This causes a lack of uniformity in the size of each part, that is, at), au, [0 and fa of the H-sectioned steel member shown in FIG. 4.

Such troubles will be explained with reference to FIG. 4. As mentioned above, in the universal rolling mill of conventional type, the contacting line of the vertical rolls with the flange I is ahead of that of the horizontal rolls with the web 2. Therefore, the rolling mill running on the roller table 4 by its own weight, first catches the flange l with the side wall of the horizontal rolls H and the vertical rolls V, and then its horizontal rolls H bite the web 2 of the to-be-rolled material. The biting points of these rolls are indicated with Y and Y respectively. In this case, if the distance hx from the upper surface of up is produced therebetween tending to hold down the flange I. Then the web 2 is bitten into the space between the horizontal rolls H, and H and it tends to move to the center of the space between the horizontal rolls, that is, upwardly.

Therefore, the product discharged from the rolling mill will have such section as shown in the right part of FIG, 4, with the center Z-Z of the web 2 having moved above the center Y- Y of the height of the flange 1. It is generally nearly impossible to set the rolls so that the upper surface of the roller table 4 set before or after the rolling mill is levelled with the center XX of the space between the upper horizontal roll H, and the lower horizontal roll H There have been developed some devices to make the roller table 4 movable up and down and adjust its height to the pass line as much as possible every time the to-be-rolled material passes. But when using such devices, the width of the flange l of the to-be-rolled material get slightly bigger as it passes the rolls, and it is very difficult to minutely adjust the height of the roller table to meet such growing width of the flange.

The method of the present invention is presented to solve these troubles, and is characterized by adjusting the ratio of diameters between the vertical roll and the horizontal roll and/or the schedule of each pass for the reduction of the flange and the web so that the biting of the web by the horizontal rolls is made at almost the same position as or in advance of the biting point of the flange by the vertical rolls.

An example of the actual rolling operation for the production of a H-sectioned steel member according to the present invention is described, using the drawings, as follows:

FIG. 3 shows an embodiment of the present invention, wherein the diameter of the horizontal rolls H is made greater than that of the vertical rolls V so that the biting points Y,,- Y of the web 2 precede the biting points Y,-Y,-of the flange l and the ratio between their projected lengths in contact with the rolls is adjusted to be ldH IdV. For this purpose, as shown in FIG. 5, the biting points Y,,Y of the web 2 precede the biting points of the flange l; the web 2 of the to-be-rolled material is bitten by the horizontal rolls H, and H independently of the surface level of the roller table 4; the flange l forming one body with the web 2 is lifted up as it is in the original form and positioned rectangular against the axes of the horizontal rolls H, and H and then the flange l progresses into the space between the horizontal rolls H, and H and the vertical rolls V,, thus the rolling operation starts. Therefore, after it has passed through said rolling mill, the material turns out to be a H-sectioned steel member having a uniform sectional shape. (See FIG. 5) The following is a description of the ratio of diameters of the rolls for use in the practice of the present invention. (See FlG. 3)

Reduction of the flange Ahf= TFo-TF Reduction of the web Ahw TWo-TW Therefore, the general ratio between the reduction of the flange and that of the web is TF/TW= Ahf/Alm- Assuming that this ratio is 1.6, Ahf= 1.6 kw The projected length of the roll in contact with the to-berolled material is expressed by Id 1/ Ah'R Where All is a reduction and R is the radius of the roll. Therefore, the projected lengths of respective rolls in contact with the to-berolled material are IdH =1/ NIW'RH and ldV V AhfZRV Where RH the radius of the horizontal roll and RV the radius of the vertical roll. As for the rolling by the vertical rolls, the inside of the flange is not reduced, therefore, the diameter of the vertical roll is used, in the above formula instead of the radius while the radius is used in the case of the horizontal roll.

Assuming [hill Ill! Ill/l. MEI 27?! VX754 'RI'I J 1- If!" I; A/lw a That is, for obtaining a ratio of less than H) in reduction between the flange and the web, the use of a ratio of more than 3.2 in diameter between the horizontal rolls and the vertical rolls will solve all such troubles as the production of piling aws and scratches and lack of uniformity in the shape of the rolled products.

The following is to explain the diagram for comparing the examples of the conventional method and of the present invention:

FIG. 7 shows the histogram of the shifting from the center of the web of a H-sectioned steel member having a 300 mm wide flange and a 300 mm high web by the universal rolling mill of conventional type. When compared with FIG. 7, FIG. 8 showing such histogram obtained by using the method of the present invention, proves that the shifting from the center of the web with the present method takes place about half as often as resulted from the use of the conventional method. In FIG. 7 and FIG. 8, the vertical axis indicates the numbers N of H-sectioned members rolled on tests; and the horizontal axis indicates the numbers of those among the abovementioned of the so rolled members, in which shifting SW from the center of the web took place. Also, FlG. 9 shows that the irregularity in the distance so shifted in the lengthwise direction of the to-berolled material in the case of using the rolling mill of the present invention (A) is much less than that in the case of using the mill of conventional type (B). In FIG. 9 the vertical axis indicates the shifting SW from the center of the web; and the horizontal axis indicates the positions of the top T, the middle M and the bottom B of the rolled material in the lengthwise direction LD.

The above explanation of the present invention is made by using a H-sectioned steel member as an example, but, not limited to this kind of rolled product, the present invention applies to the rolling of all shaped steel members similar to the H-sectioned steel member such as rails and l-sectioned steel members.

In the explanation of the precedence of the biting point of the web, a ratio of 1.6 in reduction between the flange and the web is taken as an example, but such a method of determining the schedule of reduction at each pass from the preestablished ratio in diameters of the rolls, and the combination of this method and the aforementioned method are within the scope of the present invention.

As mentioned above, .use of the present invention will make it possible to produce shaped steel members having flanges with very few defects, and at high accuracy in size economically and easily. 7

What we claim is:

1. ln a method for rolling shaped steel members having at least one flange such as H-sectioned steel members and rails by using a universal rolling mill having the axes of the vertical rolls and the horizontal rolls in the same vertical section, the improvement comprising moving the to-be-rolled material through said universal rolling mill, causing said horizontal rolls to contact the web of said material prior to the point at which said vertical rolls contact said flanges of said material, and adjusting the ratio between diameters of said horizontal rolls and said vertical rolls to be greater than 3.2, whereby the reduction ratio of said flanges to said web is less than 1.6.

2 X lliA/rm j), v A/lm m m 

1. In a method for rolling shaped steel members having at least one flange such as H-sectioned steel members and rails by using a universal rolling mill having the axes of the vertical rolls and the horizontal rolls in the same vertical section, the improvement comprising moving the to-be-rolled material through said universal rolling mill, causing said horizontal rolls to contact the web of said material prior to the point at which said vertical rolls contact said flanges of said material, and adjusting the ratio between diameters of said horizontal rolls and said vertical rolls to be greater than 3.2, whereby the reduction ratio of said flanges to said web is less than 1.6. 